A SURVEY OF THE RESULTS OF HEMATOLOGICAL PARAMETERS, USING A COMMON-RAT BLOOD-SAMPLE IN JAPANESE LABORATORIES

A survey was conducted to determine the accuracy and quality control o f automated haematology analysers used in non-clinical toxicity studie s. Pooled blood samples from male Sprague-Dawley rats were distributed to 98 laboratory facilities throughout Japan, the samples being deliv ered under refrigeration to each facility within 18 h of sample prepar ation. At each facility, the samples were analysed within 4 h of recei pt. Commercially available normal human blood samples from a single lo t were also analysed at the same time. Most haematological results wer e within the mean +/- 3SD (standard deviation), but some facilities ga ve either high or low values consistently for both human and rat sampl es. No facility gave high or low values to certain parameters sporadic ally, which suggests no problem with the accuracy of the equipment. Ho wever, it was suspected that there would be some problem in comparing analytical values determined in a unique way by specific equipment des ign. The use of certain equipment resulted, in rat haematocrit values in particular, being either too high or too low. In these cases, it wa s deemed necessary to make some adjustments or calibration changes. Th ere were also platelet values with a 'plus drift' which was apparently due to contamination with, or failure to identify small red blood cel ls (RBC). There was no deviation in values which could be attributed s olely to the mechanical operation of any of the analytical equipment. Non-standard, initial setting up of the equipment (originally intended for human use, but now used for a variety of animal species) has been recognised as the main cause for a wider range of the analytical valu es seen. The results of this survey suggest that it may be necessary t o review equipment calibration at each facility, and to re-establish t he historical background data.